LEGACY OF MOSES HAILED

By JOYCE PURNICK, Special to the New York Times

Published: August 1, 1981

BAY SHORE, L.I., July 31—
Robert Moses, the builder of so much that is now New York, was memorialized here today in a church that is virtually surrounded by examples of the bridges, causeways and parkland he left as his legacy.

As the flag flew at half-staff outside St. Peter's by the Sea Episcopal Church, Mr. Moses was praised and remembered for imposing a new landscape on the state, for changing it and, in the process, shaping pieces of its future in ways that have since been both commended and criticized.

''He was a visionary, because it takes a visionary to make a better world,'' the Very Rev. Donald S. McPhail, former rector of St. Peter's, told 300 friends, family members and elected officials -past and present. ''This man gave us bridges to beaches, parkways to power stations.''

In silent testimony to that statement lay the geography immediately without the church: the Robert Moses Causeway, which leads from the Southern State Parkway across the Robert Moses Twin Causeway to the Robert Moses State Park on Fire Island. Mr. Moses built all of that, and many other projects. An Opponent of Westway

He did more ''for New York's common man,'' said the Rev. Lawrence McGinley, a friend of Mr. Moses, ''than the Pharoahs did for Egypt in all their might.''

The service for Mr. Moses, who died of heart failure Wednesday at the age of 92, came on the same day the city and state reached accord on the Westway, one of the most ambitious construction projects ever undertaken in New York.

Mr. Moses opposed the Westway, and in a 1974 statement said: ''I am for public works and for government aid within reason, but my imagination is staggered by the demand of a 90 or even 50 percent handout at Washington for a race track highway on the West Side of Manhattan.''

The Federal Government will pay for 90 percent of Westway's construction and the state will pay the remaining 10 percent. Mr. Moses was born into a prominent Jewish family on Dec. 18, 1888, but some time after attending Yale and Oxford Universities, he decided he would rather follow the Episcopal faith.

Governor Carey, speaking to reporters, said of Mr. Moses: ''He saw what had to be done and he didn't let little rules and regulations get in his way.'' 'A Tough Opponent'

Former Mayor Robert F. Wagner of New York described Mr. Moses as a ''tough opponent, a fighter.'' Dr. William J. Ronan, longtime secretary to the late former Gov. Nelson A. Rockefeller, recalled a professional lifetime of jousting with Mr. Moses.

Mayor Koch, who fought Mr. Moses' unsuccessful plan to build an expressway in lower Manhattan, complimented the builder as a ''tough adversary.'' His argument against that roadway had been the same as other criticisms of some Moses projects - that it would dispossess people and disrupt a neighborhood for the benefit of automobile riders. Still, the Mayor added, ''If you took the pros and cons, you have to come up with a huge plus.''

Attending the service were three generations of the Moses family, including Robert Moses' second wife, Mary Grady Moses; his daughters, Barbara Olds and Jane Collins; his granddaughters, Nancy Sloan and Caroline Hunt, and some of his six great-grandchildren.

Illustrations: photos of the funeral of Robert moses photo of members of the Moses family (p.27)